The shear stress of flowing blood on endothelial cells lining blood vessels and associated mass transport are important in the acute modulation of vascular tone, chronic remodeling of the vessel wall, and localization of atherosclerosis. Knowledge of in vivo wall shear stresses in curved and branched arteries under physiological conditions is limited by the inadequate spatial resolution of available blood flow diagnostic techniques. Thus, one of the broad objectives of the proposed research is to determine the magnitude and spatial distribution of wall shear stress and solute mass flux in complex arterial geometries under realistic physiological flow conditions. Interstitial fluid flow arises from the pressure gradient across the vessel wall. This flow exposes medial smooth muscle cells to shear stresses of the same order of magnitude as shear stresses on endothelial cells. The second broad objective of the proposed research is to improve estimates of interstitial flow shear stress and mass flux and extend understanding of the physiological response of smooth muscle cells to shear stress. The specific aims of the proposed research are: 1) to measure wall shear rate in elastic curved and branch artery models with non-Newtonian blood analog fluids under physiological flow conditions simulating normal and vasoactive drug altered states; 2) to compute wall shear stress and mass flux distributions in curved and branch arteries with high spatial resolution; 3) to simulate interstitial fluid flow driven by the transmural pressure gradient and compute the associated shear stress and mass flux on smooth muscle cell surfaces; and 4) to determine the biochemical response of vascular smooth muscle cells to physiological levels of shear stress.